Document feeding mechanism



April 14, 1970 E. F. LINDQUIST ,5

DOCUMENT FEEDING MECHANISM Filed 001;. 6, 1967 2 Sheets-Sheet '1 FIG 2 DIRECTION 'OF TRAVEL I F 3 INVENT OR 34 i n EVERET F, LINDQUIST i BY Ml 7 f H ATTORNEY- April 1970 L E; F. LlNDQUlST 7 DOCUMENT FEEDING MECHANISM 2 Sheets-Sheet 2 Filed Oct. 6. 1967 INVENTOR ATTORNEY DIRECTION OF TRAVEL EVERET F. LINDQUIST United States Patent 3,506,258 DOCUMENT FEEDING MECHANISM Everet F. Lindquist, Iowa City, Iowa, assignor to Measurement Research Center, Inc., Iowa City, Iowa, a not-for-profit corporation of Iowa Filed Oct. 6, 1967, Ser. No. 673,455 Int. Cl. B65h 1/06 U.S. Cl. 27141 16 Claims ABSTRACT OF THE DISCLOSURE This invention relates to feeding mechanisms, and more particularly to an improved mechanism for feeding successive documents edgewise along a support surface from the end of a stack of documents supported by the surface.

It is well-known in the prior art to feed sheets of paper, cards, letters, booklets, or the like, referred to hereinafter collectively as documents, successively from the end of a stack of such documents, with the stack being supported in engagement with the surface along which the individual documents are fed. Such document feeding mechanisms are commonly referred to as bottom feeding mechanisms, since they are commonly employed to feed documents from the bottom of a vertical stack of documents urged by gravity into contact with the bottom supporting surface over which they are fed. Such devices may be used, however, to feed successive documents from the end of a stack of documents disposed in any orientation by providing means for urging the end of the stack into continuous engagement with the supporting surface. Thus, while applicants invention will be illustrated and described in connection with a mechanism for feeding the successive documents from the bottom of a vertical stack of documents, it should be understood that the invention may be employed to feed documents regardless of the orientation of the stack.

The prior art bottom feeding devices, mentioned above, have normally employed a driven feeding means such as a belt or friction roll for frictionally engaging and sliding the bottom document from beneath the stack. To provide sufficient frictional contact between the feeding means and the document to feed the document from beneath the stack, while at the same time avoiding abrasion, wrinkling, tearing or otherwise damaging the document, it has generally been necessary for these prior art devices to engage a substantial portion of the area of the document being fed. This has been particularly true of devices employed to feed relatively thin, flexible documents such as single sheets of bond paper or the like. Once the feeding operation is initiated and the bottom document has been fed a portion of the way from beneath the stack, a much smaller friction force is required to continue the feeding operation. However, the prior art document feeding devices of this general type have not been capable of varying the friction force applied to the document as the document is fed from the hopper, with the result that excessive force was frequently applied toward the trailing edge of a document being fed. Also, these prior art devices frequently engaged and applied a feeding force directly to a subsequent document before the document being fed was completely withdrawn from beneath the stack, thereby tending to force more than one document from the stack at a time.

Accordingly, the primary object of the present invention is to provide an improved mechanism for feeding successive documents edgewise over a supporting surface from the end of a stack of documents supported by a surface.

Another object is to provide such a document feeding mechanism including means for frictionally engaging a document to be fed through openings in the supporting surface.

Another object of the invention is to provide such a document feeding mechanism in which the feeding force applied to a document is varied as the document is fed along the support surface.

In the attainment of the foregoing and other objects, an important feature of the invention resides in providing a mechanism for feeding a document along a supporting surface by frictional contact with driven feeding means projecting through the supporting surface to engage the document. The area of contact between the document and the friction feeding means is decreased as the document is fed along the supporting surface so that the feeding force applied to the document by the feeding means decreases as the document is fed. This feeding force may be varied in steps, from a maximum at the beginning of the feeding cycle, and reduced progressively as the document is fed along the surface. Although the feeding means is continuously driven, the feeding of a document is completed before feeding of a subsequent document is initiated.

Other objects and advantages of the invention will become apparent from the following specification, taken with the drawings, in which:

FIG. 1 is an elevation view, in section, of a document feeding mechanism according to the present invention;

FIG. 2 is a view similar to FIG. 1, with certain parts shown in an alternate position during the feeding cycle;

FIG. 3 is an elevation view of the feeding mechanism, shown in FIG. 2, as seen from the discharge end of the mechanism;

FIG. 4 is a top plan view of the mechanism shown in FIG. 1;

FIG. 5 is a view similar to FIG. 1, and illustrating an alternate embodiment of the invention;

FIG. 6 is a view similar to FIG. 5 with certain parts shown in alternate position during the feeding cycle;

FIG. 7 is a fragmentary elevation view, on an enlarged scale, of the mechanism shown in FIG. 6, as seen from the discharge end of the mechanism; and

FIG. 8 is a fragmentary sectional view, taken on line 88 of FIG. 7, with certain parts broken away to more clearly illustrate other parts.

Referring now to the drawings in detail, a document feeding mechanism according to the present invention, indicated generally by the reference numeral 10, is illustrated as including a frame comprising a pair of laterally spaced, elongated base plates 11, 12 joined along their upper edges by elongated horizontally disposed support plate 13. Supported on and extending above one end of the support plate 13 is a hopper 14 including a vertically extending end wall 15 and a side wall 16, with the support wall 13 forming the bottom wall of the hopper and extending outwardly therefrom to define a support surface 17 for a stack of documents 18 to be fed from the hopper. End wall 15 has an elongated opening formed therein along the lower edge thereof at its intersection with the bottom wall of the hopper to define a feed opening 19 for the hopper.

To feed the individual documents 18a edgewise from the bottom of the stack 18, through the feed opening 19 and over the support surface 17 of plate 13, three feed roll assemblies 20, 21 and 22 are mounted on the frame beneath the hopper 14. Since the separate feed roll assemblies are quite similar in construction, only assembly 20 will be described in detail, with similar reference numerals being employed to indicate corresponding parts of the remaining feed roll assemblies, with the suffix a being employed to indicate parts of the feed roll assembly 21, and suffix b indicating parts of assembly 22.

Feed roll 20 comprises a shaft 25 mounted for rotation by suitable antifriction bearings 26 supported by the base plates 11 and 12. A plurality of annular feed wheels 27 are rotatably fixed at spaced interval along the length of shaft 25 for rotation therewith, and a resilient high friction drive shoe 28 is mounted, as by bonding, to the outer periphery of each of the wheels 27. The drive shoes 28 extend part way only around the outer periphery of the wheel 27 with the shoes 28 being aligned along the length of the shaft 25.

Referring to FIGS. 1, 2, and 6, the circumrefential length of the high friction shoes varies with the position along the hopper, with the longer shoes being closest to the feed opening 19 of the hopper and the shorter shoes being closest the end of the hopper opposite the end wall 15. Thus, the feed shoes 28 are substantially longer than feed shoes 28a which, in turn, are substantially lohger than shoes 28b. Ideally, the length of the individual friction shoes will be substantially equal to, but no greater than the horizontal spacing of the associated supporting shaft 25 to the trailing edge of a document supported in the hopper in position to be fed, as will be more fully explained hereinbelow.

The support plate 13 is provided with a plurality of openings 30, with each of the feed wheels 27 being positioned adjacent one of the openings and with the outer peripheral surface of the individual wheels in juxtaposition to the support surface 17 of the plate 13. The friction shoes 28 are of sufficient radial thickness to project through the openings 30 into the interior of the hopper 16 to engage the surface of a document supported on surface 17 to frictionally drive the document through the opening 19. Preferably, the shoes project into hopper 16 a distance to slightly lift the stack of documents 18 from engagement with surface 17 to thereby reduce the frictional drag ori the document being fed. However, it is important that the peripheral areas of the drive wheels 27 which are not covered by the friction shoes 28 do not contact a document in the hopper with sufficient force to frictionally drive the document from the hopper. Ideally only the friction shoes 28 project into the hopper 16 to contact and feed the documents.

The feed roll assemblies 20, 21 and 22 are driven in synchronization with one another by suitable means, such as the chains 29, 29a and suitable motor means such as an electric motor, not shown. By adjusting the relative positions of the drive assemblies so that each of the friction shoes project into the hopper to engage a document simultaneously, a maximum frictional feeding force is applied at the beginning of the feeding cycle. This maximum frictional force is applied continuously until the document being fed disengages the friction shoe 28b. Thetrailing end of the friction shoe 28b passes below the feed surface 17 to disengage the document substantially as the trailing end of the document passes above the feed wheels 27b so that the friction shoe 28b does not engage the next document in the stack 18. Thus, although the feed roll assemblies are continuously driven, they can only engage a single document at any one time with suflicient force to feed the document from the hopper.

In the embodiment of the invention illustrated in FIGS. 1 through 4, a bracket 31 is adjustably mounted on the inner surface of end wall 15, as by screw 32 extending through an elongated slot 33 in the end wall 15.

An annular resilient retard element 34 is mounted on the bracket 31, as by bolt 35, in spaced relation to the support surface 17 to engage and frictionally resist movement of a document therebeneath. This frictional resistance is greater than the frictional resistance between two documents but less than that between a document and the shoes 28. Thus, the retard element is effective to prevent more than one document being fed from the hopper at a time.

The feed roll assembly 20 is positioned directly beneath the retard element 34 so that the resilient high friction shoe 28 cooperates with the resilient retard element 34 to form a soft throat area 39 in the feed opening 19 to permit documents of varying thicknesses to be fed from the hopper. While the retard element 34 is of a high friction material, it will readily yield to permit, in cooperation with resilient drive surface 28, a relatively thick document to be fed thereunder. Thus, documents of varying dimensions and characteristics such as single sheets of relatively thin bond paper, may be intermixed in the stack with relatively rigid card-like material or multiple leaf booklets and be fed one-at-a-time without any adjustment of the mechanism.

Referring now to the embodiment of the invention illustrated in FIGS. 5-8, an alternate retard means is provided in the form of a driven resilient belt 40 extending over a driven pulley 41 and a pair of idler pulleys 42, 43 mounted on a plate 44 extending along one side edge of and projecting above the support plate 13. Belt 40 is driven in a direction so that the length of belt extending parallel to and adjacent the surface 17 moves toward the feed opening 19 of the hopper to engage and frictionally resist movement of a document from the hopper over the surface 17. In this embodiment, the feed roll assembly 20 is spaced slightly from the end of the hopper, and an auxiliary feed mechanism is provided to assist in the feeding operation and to positively assure that a document is completely fed from the hopper. This auxiliary feeding mechanism comprises a movable tractor assembly 45 mounted on the base plate 11 beneath an opening 46 in plate 13. Tractor assembly 45 comprises an endless belt 47 extending over pulley 48 mounted on and fixed for rotation with a driven shaft 49 supported by bushing 50 on the plate 11, and an idler pulley 51 mounted for rotation on a shaft 51a supported by a bracket 52 pivotally mounted on shaft 49. Bracket 52 includes a downwardly projecting arm 53 having a cam follower 54 mounted on its distal end in engagement with a driven eccentric cam 55. Eccentric cam 55 is rotatably fixed on a shaft 56 rotatably supported by a suitable bearing 57 in plate 11, and driven, as by chain 58, in synchronization with the feed roll assemblies 20, 21 and 22. As illustrated in FIGS. 5 and 6, rotation of the cam 55 will pivot the bracket 52 and the idler pulley 51 about shaft 49 to move the belt 47 from a position below the surface 17 as illustrated in FIG. 5 to a position projecting through the opening 46 to extend slightly above the upper surface 17 in position to engage and assist in the feeding of a document from the hopper.

The pulleys 48 and 51 are spaced apart a distance greater than the idler pulleys 42, 43, with these latter pulleys being positioned intermediate the pulleys of the tractor assembly. With no document being fed, and the pulley 51 in its raised position, the outer surface of bolt 47 in the area extending over a pulley 51 is slightly above the lower surface of the belt 40 so that the belt 47 is in' contact with and is deflected downward slightly by the retard belt 40. Thus, a document being fed between the belts 40 and 47 will be urged into firm contact with the retard belt, and only a single document will be fed at a time. A resilient leaf spring 59 is mounted on a pin 60 supported on plate 11, and extends through the opening 46 on each side of the belt 47 in position to engage and urge a document upward into engagement with the belt 40. Thus, even with the pulley 51 in the lowered position shown in FIG. 5, a document extending beneath the belt 40 will be urged into frictional engagement with the belt.

Suitable means, such as the pinch rolls 61, 62, may be provided to convey the documents fed from the hopper away from the feeding mechanism over the supporting surface 17. These pinch rollers will also assure that a document will be completely removed from the hopper regardless of its length, once the leading edge of the document is fed into the nip of the rolls.

While preferred embodiments of my invention have been disclosed and described, I wish it understood that I do not intend to be restricted solely thereto, but that I do intend to include all embodiments thereof which would be apparent to one skilled in the art and which come within the spirit and scope of my invention.

I claim:

1. In an apparatus for feeding successive documents edgewise from one end of a stack of documents, including a wall for engaging and supporting said one end of the stack of documents, driven friction feed means mounted adjacent said wall on the side thereof opposite said stack of documents and extending through openings in said wall for engaging and feeding the documents oneat-a-time from the stack, and retard means at one edge of said stack in position to engage documents being fed therefrom to prevent the feeding of more than one document at a time, the improvement wherein said drive friction feed means comprises, a plurality of feed rolls each having high friction means on and extending part way only around the outer peripheral surface thereof, the length of said high friction means on the periphery of selected ones of said feed rolls being greater than on others of said feed rolls, mounting means supporting said feed rolls for rotation about generally parallel axes spaced along said wall and extending generally perpendicular to the direction of movement of said documents, said mounting means positioning each of said feed rolls adjacent an opening in said wall with the rolls having the longer high friction means therein mounted closer to said one edge of said stack, and drive means for rotating said feed rolls about said axis, said high friction means projecting through said opening in said wall upon rotation of said feed rolls to engage a document supported by said wall to frictionally feed the document over said wall, the frictional contact between a document supported by said wall and said feed rolls in the area thereof not having said high friction means thereon being insufficient to feed a document over said supporting surface.

2. The document feeding device defined in claim 1, wherein said drive means includes means for rotating each of said feed rolls at a uniform rate and in synchronization with one another to engage the high friction means on each feed roll with a document substantially simultaneously and to disengage the high friction means on the feed ro-lls farthest spaced from said one edge ahead of the feed rolls closer to said one edge.

3. The document feeding device defined in claim 2, wherein said high friction means comprises resilient shoe means mounted on the outer periphery of each said feed lI'Oll, said documents having a higher coefficient of friction with said resilient shoe means than with the peripheral surface of said feed rolls not covered thereby.

4. The document feeding device defined in claim 1 wherein, said feed rolls are substantially circular in cross section, said mounting means supporting said feed rolls with their outer peripheral surface spaced from a document supported on said wall, and wherein said high friction means comprises a resilient shoe mounted'on the outer cylindrical surface of each said feed roll, said resilient shoes being of sufficient thickness radially of said feed rolls to project through through said openings in said wall and engage a document supported on said wall to feed the document from said hopper.

5. An apparatus for feeding successive documents edgewise from the end of a stack of documents comprising, a hopper including a first wall providing a support surface for the stack of documents and a second wall extending from said support wall, a feed opening in said second wall at the intersection thereof with said support surface, retard means adjacent said feed opening for resisting movement of documents from said hopper, a plurality of openings formed in said first wall, a plurality of feed rolls, mounting means supporting said feed rolls for rotation about generally parallel axes spaced from said feed opening and extending generally transverse to the direction of movement of a document being fed from said hopper through said feed opening, said mounting means positioning the respective feed rolls beneath an opening in said first wall with the outer peripheral surface of said feed rolls being juxtaposed with and substantially tangential to the plane of said support surface, high friction means on and extending part way only around the outer peripheral surface of said feed rolls, the length of said high friction means on the periphery of selected ones of said feed rolls being greater than on others of said feed rolls, with the rolls having the longer high friction means thereon being mounted closer to said feed opening, and drive means for rotating said feed rolls about their respective axes, said high friction means projecting through said openings in said first wall to engage and frictionally feed a document supported on said support surface through said feed opening, the frictional contact between said feed rolls in the area not having said high friction means mounted thereon and a document on said support surface being insufficient to feed a document over said support surface.

6. The document feeding device defined in claim 5, wherein said drive means includes means for rotating each of said feed rolls at a uniform rate and in synchronization with one another to engage the high friction means on each feed roll with a document substantially simultaneously and to disengage the high friction means on the feed rolls farthermost spaced from said feed opening ahead of the feed rolls closer to said feed opening.

7. The document feeding device defined in claim 6, wherein said high friction means comprises resilient shoe means mounted on and covering a portion only of the outer peripheral surface of said feed rolls, said documents having a higher coefficient of friction with said resilient shoe means than with the peripheral surface of said feed rolls not covered by said resilient means.

8. The document feeding device defined in claim 5, wherein said feed rolls are substantially circular in cross section, said mounting means supporting said feed rolls with their outer peripheral surface spaced from a docu ment supported on said wall, and said high friction means comprises a resilient shoe mounted on the outer cylindrical surface of said feed rolls, said resilient shoe being of sufficient thickness radially of said feed rolls to project through said openings in said wall and engage a document supported on said wall to feed the document from said hopped.

9. The document feeding device defined in claim 8 wherein the thickness of said resilient shoe means is sufficient to project into said hopper to force a document out of engagement with said support surface at least in the area thereof adjacent said openings in said first wall to thereby reduce the frictional resistance to movement between a document being fed and said support surface.

10. The document feeding device defined in claim 5 wherein said first wall is substantially horizontal and said stack of documents is continuously urged into engagement with said support surface by gravity, said documents being fed through said feed opening successively from the bottom of said stack.

11. The document feeding device defined in claim 5 wherein said retard means comprises resilient stop means, and mounting means supporting said resilient stop means in spaced relation to said support surface to engage and frictionally resist movement of a document between said support surface and said resilient stop, said resilient stop being yieldable to permit documents of different thicknesses to be fed thereunder.

12. The document feeding device defined in claim 11 wherein said resilient stop means comprises an endless belt, said mounting means comprising a plurality of pulleys supporting said belt for movement along a path including a segment extending generally parallel to and in juxtaposition with said support surface, and means for driving said belt for movement along said path segment in a direction opposite to the direction of movement of a document being fed from said hopper.

13. The document feeding device defined in claim 12 further comprising a pair of pulleys mounted adjacent said first wall on the side thereof opposite said support surface, an endless feed belt mounted on said pulleys, an opening in said first wall adjacent said feed belt, means driving said feed belt around an endless path extending over said pulleys, and driven means for moving one of said pulleys toward said first wall to engage said feed belt with a document being fed from said hopper.

14. The document feeding device defined in claim 13 wherein said driven means comprises means for moving said one pulley toward and away from said first wall in synchronization with movement of said feed rolls.

'15. In a document feeding apparatus including a hopper having a wall for engaging and supporting one end of a stack of documents to be fed, said one end overlaying an opening in said wall, and driven document feed means projecting through said opening in position to engage and apply a frictional force to said one end to feed the endmost document in said stack edgewise from said hopper along said wall from said one end, the improvement comprising means on said driven feed means for varying the frictional force applied to said one end in accordance with the position of said endmost document on said wall.

16. In a power driven document feeding system in which successive documents are fed edgewise over a supporting surface from one end of a stack of documents supported on the surface by friction engagement between said one end and driven feed means extending through said support surface, the improvement which comprises the step of varying the degree of frictional engagement between said one end and said driven feed means in accordance with the position of a document being fed from said one end over said support surface.

References Cited UNITED STATES PATENTS 757,484 4/1904 McGirr 271--41 1,626,386 4/1927 Bronander 271-41 1,971,962 8/1934 Jones 271-41 3,122,040 2/ 1964 Bishop 271-41 X EDWARD A. SROKA, Primary Examiner 

